Mechanism for limiting the calling possibilities of a telephone apparatus



Oct. 8, 1940. I F A 2,216,850

MECHANISM FOR LIMITING THE CALLING POSSIBILITIES OF A TELEPHONE APPARATUS Filed Aug. 18, 1957 2 Sheets-Sheet 1 Oct. 8, 1940 MECHANISM FOR LIMITING F. MART] 2,216,850

THE CALLING POSSIBiLITIES OF A TELEPHONE APPARATUS Filed Aug. 18, 1937 2 Sheets-Sheet 2 vvvvvvv axis 40 manner.

Patented Oct. 8, 1 940 U I a 1 UNlT ED STAT I PATENT oFricE I r r 2,216,350 r IMECHANISM FOR LIMITING THE CALLING" POSSIBILITIES PARATUS I OF A ,TELEPHQNE AP Fritz Marti, La Qhaux-de-Fonds, Switzerland I Application August 18, 1937, Serial No. 159,790

I I Switzerland August19, 193 6 The invention relates to an exchange} system for a telephone withlimited calling possibilities, in whichiimpulse transmission takes place on the return movement of the impulse-dial. 'To said dial a shaft is coupled, adapted to rotate two control disks on which concentric partition walls :are arranged, whereby the walls of one of said disks have gaps corresponding to theblocked upnuinerals. Furthermore a spring-controlled l feeler, adapted to penetrate intojsaid gaps, is

provided; which feeler, at the end of its opera-.. I tion, closes acontact which,inIits turn, is capa- I bl'e ofbridging the impulse-contact.

Other ob jects and features of the invention l willbeapparent as the following description proceeds, reference being hadto' the accompanying drawings, in which I Fig; 1 isthe wiring diagram of thetwo embodiments illustrated as example. P I

tion of the firstembodiment. I I I Fig.' 3 is a partialand schematic representa tion of the second embodiment. I I j I In Fig. l-the principalfparts'of atelephone 25 station according tothe inventionfare shown. I

T indicates the receiver, IMi the microphone, Tr the transformer, D the impulse dial, C1 the switch controlled by. said dial, F the hook switchwhich closes the circuitwhen the receiveris takenofi.

I 30 With the aid of the terminals a and 'b theftelephone station is connected to the line and thus to the local exchange. The bell S of the station is connected inserieswith a condenser C which prevents the passage of direct currentkbut' lets exchangeior operating the bell. v r r -I r As may be seen from Fig, 2 dial D is provided withten digit holes distributed over thecircumference of the dial andnumbered in a known This well-known disk is fastened to a shaft carrying a ratchet wheel l2 and is under the influence of a release-springl3. A worm wheel I5 is loosely placed on shaft H, and meshes with worm l6 coupled witha centrifugal gov- 45 ernor H the rotating masses of which are rep- I resented schematically and denoted by 18 pawl "mounted on worm wheel I5, and acted I upon by spring 23, glides over the teeth of the? ratchet wheel, whenrdial ID is turned in'the, di'- 50 rection of arrow 10, but drives worm wheel and, thereby, governor II, when the dial returns in the direction of arrow H under the effect of I spring I3 which is initiallystressed. Worm wheel l5 Icarries a cam disk IS with bosses 20 distributed on its circumference in the same, way as it will be understood that switches C2, Cs, C4

* Fig.1 is a perspective, schematic representa through the alternating current supplied by the the digit holes on the impulse dial.v These bosses act on a contact 2l'of switch Ci opening'the circuit shown in Fig. 1. Referring to this Figure 1 connected in parallel With switch C1 short circuit the latter, if any of these contacts is closed and thus permit the transmission of'predetermined numbers only, it said switches are closed for all other numbers. which-one may attempt to set.

In Fig; 1, a lock Se is illustrated as a means of l I closing one of these switches, viz: C4, if lit is desired to prevent any use at the telephone station. -I r I I I I There isalso a relay B. connected in serieswith SWi'tchesCa tojCi. This relay serves the purpose 15 either to give noticethat the apparatus cannot I be used, or, in case of a prepayment telephone I station, to return the money. I I Awheel l4 isfixed to shaft ll, alternately ro tating either in the direction of arrow 1001" of 20 v arrow. This wheel Micarrie'sa pawhZS piv- I ot'ed at 29 and pressed-against stop 3i by means of spring 30." Wheel i4 servesas a connecting means between the impulse dial and the mechar nism according to 'the invention. In theembodi- I merits shown this mechanism is located-at the in the same direction by means of 'pawl' 28. Dial 5 I D isoperated in a well-known manner by intro ducing a finger'into the desired hole and by, rotating it until the finger touchesstop 12. Then the dial is let go whereupon it runs backunder the efiect ofspring l3. These two inverse movements of the dialare transmitted to shaft 25 by meshing with wheel 14.

Shaft 33 is under the influence of spiral spring 34 whose tensionincreases at ev ys ep of ratchet Wheel 32. 'This latterj wheel is held up by pawl 38 which,;in its turn, is mounted on shaft 58 and means of gear wheel 24 fixed to saidshaftand acted upon by spring 51; which latter presses pawl 38 againstratchet Wheel 32. Pin 36'',attached to ratchet wheel 1 32 bears against flexible stop 31 when wheel 32 is in its initial position. v

I The mechanism shown comprises only one 1 group of twomembers which serve the purpose of selecting between the permitted and nonpermitted subscriber-numbers, viz: in, cases where 55 I number however, in the embodiment illustrated the use of the station must be limited for any reason, be it that a subscriber wants to prevent third parties from setting up trunk connections, or that the station is a prepayment station for local calls or for special trunk calls. Since trunk connections are set up by using code numbers prefixed to the subscribers individual number and in order to prevent fraudulent use of the station, it will sufiice-to prevent the transmission of a certain digitat a certain place of the subscribers number.

The selecting members are formed by disks 35, 21 'fixed to shafts 33 and 25 respectively. Each of them carries, on one of its faces, concentric cylindrical partition walls equidistant from each other by a space which allows a feeler to-passbetween these walls. For disk 35 this feeler' is a roller 52 and for disk 2'? a roller M. The axis of these rollers are parallel to shafts 33 and 25 and parallel to shaft 34) of lever 35 carrying said rollers.,. This lever controlled by a spring 53 fixed to the frame and tendingto apply said rollers othe disks. One'arm of said lever is I ,oftherollers from "one to another of said partition walls. These walls each possess at least one. gap. through which the rollers may pass. In

disk 35 the gaps of the partition walls are located in such a way that the gap of the outermost wall, after disk 35 has been rotated one step, lies injuxtapositicn to roller 52; after disk has been moved a further step, the gap of thei second wall liesin juxtaposition to roller 42, etc. In disk 35-as many partition walls could be provided as there are digits in the subscribers the selection is limited to the; three first digits. The innermost wall is formed as ,a solid cylinder.

The ends of the l-otherpartition walls of disk 35 is shown in Fig. 2. The position of the other gaps "dependson the subscriber-numbers to be permitted or nonpermitted- In the example of Fig. 2 the transmission of the numbers 354 to 359 is excluded. To this end the outermost partition wall of disk 21 is provided with a gap on radius 3', which corresponds to the position of digit hole 3' on impulse dial D; the second partition .wallhas'a gap on radius corresponding to digit hole 5 and the third partition wall has a gap extending. over the space from radius 4 to 9. 1

Behind disk 2"! and on shaft ,25 disk 25 is provided comprising notches distributed over the circumference according to the position of the digit, holes of impulse dial D. An arm 5| is fixed to shaft 55 of arm 48. Tongue 52, is linked to arm. 5i in order to be adapted to swing about a steady position controlled by spring 53. In said steady position thetongue enters far enough into a cut-out of disc 25, so that, when it has been inclined at the commencement of rotation of disk 26 in the direction of arrow lilmarked on wheel 24 and when it has penetrated into a notch at the end of this rotation, it cannot assume an inverse inclination on the return motion of disk 25 without repelling arm 5!. The arrangement is such that this operation takes less time than disk 26 requires to turn one step. Finally lever 39 comprises an arm M by which it can-operate key 4-5 of switch C3.

Be it supposed that number 354 should be rung up. The first movement bringing digit 3 of dial D to stop l2 advances ratchet wheel 32 with the help of pawl 28 by one tooth and pawl 58 keeps the ratchet wheel in this new position, in which roller 42 is in line with radius 5 of disk 35. At the same time gap 3 of disk 2i is in juxtaposition to roller ii and notches l and 2 of disk 25 have passed tongue 52 which now engages notch 3. Dial D is now released and runs back, tongue 52 is reversed, arm 58 releases segmentifi, whereupon roller 52 drops upon the second partition wall and roller 4!, through the gap on radius 3, falls into the first partition of disk 21 and that before disk 27 has had time to go back too far. Arm Ml has thus approached key 45 by about a third of the amount required for closing the circuit at C3,. Thus it follows that the three interruptions oi the circuit produced by bossesiii at C1 in this same return movement, have been transmitted to the local eX- change. Lever s8 is now kept in position with theaid of the second tooth of segment 45 anddisk 2? is again in its initial position with roller ii in line with radius'ilii, but in the first partition of disk 2'3. Then digit 5 is dialled. Workings similar to those previously described now occur but with the difference that roller 52 drops upon the third partition wall and roller M passes through the gap on radius 5..

' Though roller 55 is now between the second and the third partitionwall switch C3 does not yet close the circuit and the interruptions caused by'dialling digit 5 are also transmitted. When,

, finally, digit 4 is dialled for the purpose of complating the transmission of number 354, roller 42 is in line with radius 3 of disk 35, and the third toothof segment 55 releasedby tooth Lil. The third partition wall of disk 2''! has a gap on radius i, so that the rollers can enter the third partitions of the selecting disks and apply to the innermost walls, i. e., to the solid cylinders. Now that lever 39 has carried out its maximum motion, arm 45 closes the circuit at C3. At the moment when this closing is effected, disk 2"! has still tocarry out almost the whole return motion, because it has, up to said moment, only run back as far as the distance required to operate the tongue. Bosses 25 of disk l9 have, therefore, not yet operated impulse contact C1 by which the subscribers number should be transmitted, so that, since the circuit is. closed at C3, the interruptions at 01 when they finally occur during further return motion of dial D into its initial position, are without any effect. Owing to the fact that one gap of the third par-' tition wall of disk 2i extends over the space of radii 4 to 9, not only the transmission of number. 354,, but: also of numbers 355 to 359 will be excluded in the same way as above described.

Lever 39 must now be returned to its initial position shown in Fig. 2. To this end the mechanism comprises a shaft 66 to which are attached: a member 65 for hanging up the receiver, a finger 59 adapted to co-operate with lever 48 and a finger 58 co-operating with pawl 58. Receiver hook 65 can be moved between two stops the upper stop;

. selected exclude the transmission of a, number in .It may be seen thatwhen the receiver ishung upon hook 65 tQQthA'IUdisengagessegment 45 at the same time as pawl 38 disengages ratchet wheel 32; Spring 34 then drives shaftz33 and disk 3 5 into their. initial position, thereby j forcing roller. 42 to ascend the ramps of disk 35am to move lever 39 jback into its initial position. During this return motion roller 4| passes through the gaps on radius of disk 21. Roller 42 now rests on the exterior partitionwalL 'Tooth 41 will engage segment .46 as soon as the receiver is taken off for a new call From. the above it results that thedigits, when steps only, then stopped for a certain period and finally released so that it causes five interruptions whenreturning into initial position. When dialling in this way tongue 52 would be operated but once, so that digit 5 would be transmitted,

35 contact spring 59 is lifted by finger 55.

without roller 4| dropping into gap 5 of thesecondpartition wall. Switch C2 serves to preventsuch a fraud. This switch is closed when the Whole mechanismis in the initial position shown in Fig.2. When moving dial D pawl 38 is turned, whereby This contact spring is formed so as tobe kept in this raised position by means of tooth B0 of lever 62 which is pivoted at 63 and pressed against the free: end of the shaft of worm l5 by means of spring 54; Contact spring 59 is provided with a lateral notch the width of which is equal to the totalof the width of lever 62 entering the notch and the height of tooth 60. On the opposite side of tooth 50 lever 62 carries a second tooth 5| of the same height as the first. Both teeth are ratchet-shaped. When contact spring 59 rises, it displaces tooth 60, lever 62, after that, returns under the effect of spring 64, whereby contact spring 59 is supported by the horizontal flank of tooth fill. At this moment governor I1 is still at rest, for it rotates only at the return motion of the impulse dial; As soon as this return motion begins, wheel l5 tends to displace worm It in the direction of arrow 13. The axial play of worm I6 is large enough to repel lever 62.

. Tooth 60 then disengages contact spring 59 which the dial is stopped during its return motion the axial thrust on the worm ceases, since ratchet wheel l2 no longer drives wheel l5 by means of pawl 22. The inertness of the rotating masses l8 of the governor cause an ulterior rotation of worm I6, whereby the stopped wheel l5 acts asa stationarynut, so that the worm is displaced to the left. Spring 64 then movesllever 62 in an anticlockwise direction whereby tooth 6| engages contact spring 59 which, in its turn, closes switch 02. The second digit is thus not transmitted to the local exchange.

The mechanism shown in Fig. 3 only differs from that of Fig. 2 by the provision of two feeler- I levers for each group of disks 35 and 21, instead of only one, whereby the station, instead of excluding the aforesaid numbers, will only transmit theselatter. r l l dis- Lever 39a differs from lever 39 by thefact that it only carries roller 4|, roller 42 is placed on a second lever-'|4, loosely arranged on shaft 40 of lever 39a. This secondlever does not cooperate with lever, 48: Thus its spring 19 constantly pressesroller 42 to disk 35. The position of lever 39a, does, as in Fig. 2, not depend on the position of disk 35 until its toothed segment has been released. From this moment its motion is limited bya pin, l5mounted on lever 14. This latter carries ashaft 11 to which lever 18 is pivoted. This latter raises key 45 when lever 14 lifts shaft Tl. Furthermore lever 18 turnsin the same direction as lever 39a when the latter is released.

Number 354 will be transmitted in the following manner; After the first rotation of dial D roller 42 is in line with radius of disk 35 and by the effect of spring 19 applied to the second partition wall. Lever 18 closes switch C3. This latter remains closed as long as roller 4| after the release of lever 39a does not meet a gap of disk 21. However, roller 4| passes through the gap on radius 3, so that lever 39a touches pin 15.

The left end of lever 18 is lowered by this motion of lever 39a and, thereby, the circuit is again opened at C3 and the interruptions at C1 are transmitted. The same workings occur when dialling the digits 5 and 4, whereby roller 4| passes on radius 5 through a gap of the second partition wall and on radius 4 through a gap of the third partition wall. Therefore, numbers 354 to 359 whi'chwere excluded in Fig. 2, are, in this embodiment, the only transmissible numbers. 'If the first digit is not a 3, roller 4| cannot pass through the first partition wall and the circuit remains closed at Cs, while, on the contrary, it'

remains open in Fig. 2.

Instead of a single group of selecting disks and feeler-levers and a switch C3, the mechanism vmight comprise several groups with various posend in a coin box means must be provided for electrically connecting the several contacts G3 with one another.

Incase the mechanism limiting the calling possibilities isseparated from the telephone station the talking line itself may serve the purpose of connecting said mechanism with said station,

whereby a device must be provided producing such impulses in said line, that shafts 33 and 25 carry out the same motions as they would do if they were driven by the mechanical means ilinto said gaps, a contact adapted to bridge said impulse-contact and to be closed at the end of the feeler operation in order to render ineffective any further operating of the impulse-dial.

2. In an exchange system according to claim 1, wherein one of the control disks is arranged to be rotated by the impulse-dial during the complete return movement of the latter, and the other control disk is arranged to be rotated one step at each series of impulses of said impulse contact. 7

3. In an exchange system according to claim 1, wherein the first of said control disks is arranged to be rotated by the impulse-dial during the complete return-movement of the latter and the second disk is arranged to be rotated one step at each series of impulses, a toothed segment integral with said feeler and a spring controlled arm carrying a stop adapted to co-operate temporarily with said segment to permit the feeler to come into contact with the second control disk. I 4'. In an exchange system according to claim 1, wherein the first of said control disks is arranged to be rotated by the impulse-dial during the complete return movement of the latter and the second disk is arranged to be rotated one step at each series of impulses, a toothed 'segluent integral with said feeler and a springcontrolled arm carrying a stop adapted to cooperateternporarily with said segment to permit the feeler to come into contact with the second control disk and a notched disk provided with a gap and integrally connected to the first controldisk and a spring controlled pivoted tongue mounted on the axis of said stop-carrying arm and arranged to cooperate with said notched disk to render said stop-arrangement temporarily in effective.

FRITZ MARTI. 

